Abstract
A simple and economical method for differentiating B. asaccharolyticus of oral sources from nonoral sources [human] is described. Oral strains of B. asaccharolyticus strongly agglutinate sheep erythrocytes; isolates from various nonoral sites typically are devoid of hemagglutination activity. The direct hemagglutination test may aid in determining the source of B. asaccharolyticus present in an infection, and thus the procedure has potential value as a means of biotyping.